Intermittent power failure

My second generation Prius started, moved, shut down, and failed to restart a moment later. Dashboard dark.I checked battery voltage and charge state normal. I pulled AM2 fuse, looked good, reinstalled fuse, car started and returned to my garage. Later on startup normal, shut down. Later on dashboard dark, no start, voltage on front fuse box terminal low, removed and installed AM2 fuse, relay clicking heard, terminal voltage low.

 

Battery connections appear clean, no voltage drop between negative and chassis. If it is a poor connection, it’s an intermittent condition. When the fuse was cycled out and in, the dashboard was bright and operation was normal. I suspect some relay is failing?